(a) Field of the Invention
This invention relates to a pH monitoring kit. In particular it is directed to such pH monitoring kit for the monitoring of "acid rain" and for the determination of the pH of rivers and lakes to ascertain which species of fish can survive in such rivers and lakes.
Acidic compounds contain hydrogen ions when dissolved in solution. The stronger the acid, the more hydrogen ions it contains. The more ions, the more destructive the acid. Acidity is measured on the pH scale which runs from 1 to 14. The scale is logarithmic; one pH unit represents a factor of 10 hydrogen ions. Thus, pH 5 solutions contain 10 times more hydrogen ions than pH 6 solutions, 100 times more hydrogen ions than pH 7 solutions, and so on.
Normal rain has a pH in the range of 5.6 to as low as 2.0, which is slightly acidic because carbon dioxide present in the atmosphere forms carbonic acid in the rainwater. Acid rain is about 30 to 300 times more acidic than "normal" rain, ranging from pH 4.5 to as low as pH 2.0.
Acid rain may vary qualitatively from place to place and time to time. Present day rains contain nitric acid plus sulphuric acid in changing proportions. Nitric acid forms in the atmosphere from water vapour plus nitrous oxides (N0.sub.x), which are common components of automobile exhaust. Sulphuric acid starts out in coal. Sulphur released during coal combustion becomes sulphur dioxide (S0.sub.2) and other sulphur oxides. The addition of water in rain results in the production of sulphuric acid.
Before sulphur oxides and nitrous oxides fall to the ground as acid rain, they can stay in the atmosphere for up to five days. Dead lakes are the most traceable victims of acid rain. Lakes all over the world are dead or dying, particularly where soils are thin and the bedrock is granite. Vulnerable areas include Scandinavia (30,000 acid lakes), the Canadian Shield (14,000 dead lakes, 300,000 to 600,000 lakes at risk), the New York Adirondacks (200 dead lakes, thousands dying) plus mountain lakes in Colorado and California.
Acid rain also attacks trees from several flanks; it damages the tree directly, the leaves being the prime targets; indirectly it upsets the balance of soil nutrients necessary for tree growth.
In Sweden, one spruce tree in four and one pine tree in seven are losing needles at an alarming rate. Throughout Europe 7 million hectares of forest--an area roughly the size of England--have been damages by acid rain and by other pollutants. In Canada and the United States the entire maple syrup industry, which depends on healthy sugar maples, is at risk.
Acid rain compromises the health of plants and animals, including humans. It promotes or prolongs chest colds, stuffY noses, bronchitis, allergies--maybe even lung cancer.
The United Nations Environment Programme estimates 600 million city dwellers worldwide are at risk from its effects.
Acid rain poisons fish and the animals that eat them. It speeds up heavy metal leaching from soils and pipelines. Toxic metals accumulate in animal tissues and drinking water, climbing higher and higher up the food chain.
Even buildings, roads and other human creations are not safe. Acid rain speeds up building deterioration 100 times.
Acid rain exacts tremendous costs. Tourism, agriculture, fisheries, forestry, construction and health care are all effected. Accordingly, it is exceedingly desirable to monitor acid rain.
(b) Description of the Prior Art
Many patents have issued which are directed to acid indicators which may be used to monitor acid rain. For example, Canadian Patent Number No. 735,807 patented June 7, 1966 by B.J. Eiseman Jr. provided acid-base test papers or other cellulosic materials.
Canadian Patent Number No. 686,024 patented May 5, 1964 by G.F. Collins provided test units in dry form, in which a bibulous carrier, e.g., absorbent paper, was impregnated with a pH indicator which provided a colorimetric indication of hydrogen ion concentration.
Canadian Patent Number No. 712,088 patented June 22, 1965 by John Rebar, Jr. et al provided a pH test portion of a "dip and read" type of indicator test strip.
Canadian Patent Number No. 1,186,202 issued Apr. 30, 1983 to M. Blumenthal, and its corresponding U.S. Pat. No. 4,349,353 patented Sept. 14, 1982 provided a test kit for determining the amount of soaps or other alkaline substances in fat. The test kit comprised a test solution and a set of standardized colors. The test solution comprised a pH indicator dye having a visible color change in the pH range of from 2.5 to 7.0 and a solvent in which the dye was soluble and with which the fat was immiscible. The dye and solvent were present in the test solution in amounts effective to provide a visible color change which depended upon the amount of alkaline substances, e.g., soaps, in the fat. The pH of the test solution was such that the color of the test solution prior to the mixing step corresponded to the color of the dye at the lower end of the color change range for the dye. After mixing, the fat and test solution were allowed to separate into a solvent phase and a fat phase. The amount of alkaline substances in the fat was then determined from the color developed in the solvent phase by comparing the developed color to a known standard, e.g., visually, in a coorimeter or in a spectrophotometer. The test of colors was standardized so that each color corresponded to a color developed when a predetermined amount of test solution was mixed with a predetermined amount of fat containing a specified amount of alkaline substances. The kit could also contain other apparatus for performing the method, e.g., test tubes, dispensing bottles, caps for the test tubes, droppers, ladles, test tube holders, etc.